<template>
    <div class="app-container">

        <el-button :loading="downloadLoading" style="margin-bottom:20px" type="primary" icon="el-icon-document" @click="handleDownload">Export</el-button>

        <el-table
            ref="multipleTable"
            v-loading="listLoading"
            :data="list"
            element-loading-text="Loading"
            border
            fit
            highlight-current-row
        >
            <el-table-column align="center" label="Id" width="95">
                <template slot-scope="scope">
                    {{ scope.$index }}
                </template>
            </el-table-column>
            <el-table-column label="Main Information" align="center">
                <el-table-column label="Title">
                    <template slot-scope="scope">
                        {{ scope.row.title }}
                    </template>
                </el-table-column>
                <el-table-column label="Author" width="110" align="center">
                    <template slot-scope="scope">
                        <el-tag>{{ scope.row.author }}</el-tag>
                    </template>
                </el-table-column>
                <el-table-column label="Readings" width="115" align="center">
                    <template slot-scope="scope">
                        {{ scope.row.pageviews }}
                    </template>
                </el-table-column>
            </el-table-column>
            <el-table-column align="center" label="Date" width="220">
                <template slot-scope="scope">
                    <i class="el-icon-time" />
                    <span>{{ scope.row.timestamp | parseTime('{y}-{m}-{d} {h}:{i}') }}</span>
                </template>
            </el-table-column>
        </el-table>

    </div>
</template>

<script>
import { fetchList } from "@/api/article";
import { parseTime } from "@/utils";

export default {
    name: "MergeHeader",
    data() {
        return {
            list: null,
            listLoading: true,
            downloadLoading: false
        };
    },
    created() {
        this.fetchData();
    },
    methods: {
        fetchData() {
            this.listLoading = true;
            fetchList(this.listQuery).then(response => {
                this.list = response.data.items;
                this.listLoading = false;
            });
        },
        handleDownload() {
            this.downloadLoading = true;
            import("@/vendor/Export2Excel").then(excel => {
                const multiHeader = [["Id", "Main Information", "", "", "Date"]];
                const header = ["", "Title", "Author", "Readings", ""];
                const filterVal = ["id", "title", "author", "pageviews", "display_time"];
                const list = this.list;
                const data = this.formatJson(filterVal, list);
                const merges = ["A1:A2", "B1:D1", "E1:E2"];
                excel.export_json_to_excel({
                    multiHeader,
                    header,
                    merges,
                    data
                });
                this.downloadLoading = false;
            });
        },
        formatJson(filterVal, jsonData) {
            return jsonData.map(v => filterVal.map(j => {
                if (j === "timestamp") {
                    return parseTime(v[j]);
                } else {
                    return v[j];
                }
            }));
        }
    }
};
</script>
